Shares issued under the 2017 Employee Stock Purchase Plan during the three months ended March 31, 2023 and 2022, totaled 31,639 and 31,406, respectively.

A summary of stock option activity is as follows:


	Number of Shares	Weighted Average Exercise Price ($)		Weighted Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value of In-the-Money Options ($)
Outstanding as of December 31, 2022	1,221,219	$	19.00
Exercised	(4,992)	15.88

Expired	(4,614)	19.63
Outstanding as of March 31, 2023	1,211,613	$	19.01	2.46	$	9,658,883
Exercisable as of March 31, 2023	1,211,613	$	19.01	2.46	$	9,658,883

The total intrinsic value of stock options exercised during the three months ended March 31, 2023 and 2022, was less than $0.1 million and $0.9 million, respectively. There were no stock options granted during the three months ended March 31, 2023 or 2022.

A summary of nonvested total shareholder return awards ("TSRs") is as follows:


	Number of Shares	Weighted Average Grant Date Fair Value
Nonvested as of December 31, 2022	1,011,881	$	39.21


Forfeited	(38,728)	43.99
Change in payout rate	(427,685)	30.01
Nonvested as of March 31, 2023	545,468	$	46.09

At March 31, 2023, the TSRs granted in 2020 were earned by the employees. However, the performance goals were not met and no shares were issued.

The fair value of TSRs granted during the three months ended March 31, 2022, were estimated on the date of grant using the Monte Carlo simulation model, acceptable under ASC 718, Compensation - Stock Compensation, using the following weighted average assumptions:



	Three Months Ended March 31, 2022
Expected life (years)	3.1
Risk-free interest rate	1.5	%
Expected volatility	40.0	%
Expected dividend yield	—

A summary of nonvested restricted share unit awards ("RSUs") is as follows:


	Number of Shares	Weighted Average Grant Date Fair Value
Nonvested as of December 31, 2022	1,184,024	$	30.73

Vested	(333,812)	31.10
Forfeited	(103,379)	31.75
Nonvested as of March 31, 2023	746,833	$	30.43

During the three months ended March 31, 2023, a total of 333,812 RSUs vested. The Company withheld 114,492 of those shares to pay the employees’ portion of the minimum payroll withholding taxes.

As of March 31, 2023, there were unrecognized compensation costs of $18.5 million and $10.2 million related to nonvested RSUs and TSRs, respectively, which the Company expects to recognize over weighted average periods of 1.8 years and 1.7 years, respectively.